JP2009-171733A discloses an electric powered vehicle which has a battery chargeable from an external power supply and a charging device for charging the battery. The charging device provides an electric power supply controller for vehicle. This device has a connection check function which checks and confirms physical connection between the charging device and the vehicle.
The connection check function may be provided by supplying a monitor signal to a signal line disposed in a connection cable. In one example, a charging device supplies a monitor signal to a signal line. Impedance in a circuit including the signal line would change responsive to a connection state or a non-connection state. The charging device detects change of impedance based on change of the monitor signal.
For example, a monitor signal with a predetermined voltage is supplied as a monitor signal. Voltage on the signal line is changed in response to change of impedance in the circuit containing the signal line which reflects whether the cable is in the non-connection state, or is in the connection state. The charging device may check and confirm connection by detecting the voltage on the signal line. The charging device supplies the predetermined voltage to the signal line when the charging device is ready to supply power. The charging device does not supply the predetermined voltage to the signal line when the charging device does not supply power. Such a connection check function is known, for example as a CPLT method (Control Pilot signal method.)